The Good and the Dangerous of Attic Followers | Residence & Backyard
Fans or powered attic fans are used to cool the attic, push out the hot attic air and create a cool outside air flow.
By Jeff Stock, owner of Elk Ridge Electric
The recent hail storm and the replacement of everything related to the roof has left many of us dealing with attic fans and wondering what exactly these fans are doing. Roof fans are often located on the roof and often need to be repaired or replaced after hailstorms. There are really two categories of attic fans; all the house fan and the more common powered attic fan.
Whole house fans are specially designed to use the outside air to cool your home at night. Whole house fans are best for dry climates like ours, where the temperature drops at night. The fan is mounted in the attic and is located above a central hallway in the house. To operate, the windows in the house are opened and the fan switched on. The outside air is then drawn in through the windows and through the attic where the hot indoor air is vented from the house.
Whole house fans are very energy efficient; Use only 10-15% of the energy consumed by a central air conditioning system. They are also time efficient. In general, they can cool a home in less than an hour. As soon as the house has cooled down, the fan can be switched off and the windows closed. The windows stay closed until the next evening so that no cool air can escape.
Whole house fans take all of the hot air out of the house and move it in and out of the attic through the roof vents. Because of this, they need significant ventilation in the attic. Often their ventilation requirements exceed the minimum prescribed in building codes. Although people complained that fans were loud all over the house, much quieter models are available today. The ventilation opening must be closed in the winter months. Whole house fans are now also available with built-in motorized doors as part of the unit. These doors open and close without having to crawl into the attic to seal the device.